The invention relates to an apparatus for measuring a natural period of liquid in a pressure generating chamber disposed in a head member, wherein the head member comprises a nozzle orifice communicated with the pressure generating chamber storing liquid; a liquid supply channel for supplying liquid to the pressure generating chamber; and a piezoelectric member which deforms the pressure generating chamber, to thereby cause the nozzle orifices to eject liquid droplets. Such a head member is employed in various applications.
For instance, a head member which ejects ink droplets as liquid droplets is used as a recording head of an ink jet recording apparatus for effecting recording on recording paper or the like.
Measurement of a natural period of liquid stored in the pressure generating chamber of such a head member is useful for more accurate control of ejection of liquid droplets.
However, there has not yet been realized an apparatus for measuring with sufficient accuracy the natural period of liquid stored in a pressure generating chamber.